'\" t .TH "TIMESYNCD\&.CONF" "5" "" "systemd 256.6" "timesyncd.conf" .\" ----------------------------------------------------------------- .\" * Define some portability stuff .\" ----------------------------------------------------------------- .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .\" http://bugs.debian.org/507673 .\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .ie \n(.g .ds Aq \(aq .el .ds Aq ' .\" ----------------------------------------------------------------- .\" * set default formatting .\" ----------------------------------------------------------------- .\" disable hyphenation .nh .\" disable justification (adjust text to left margin only) .ad l .\" ----------------------------------------------------------------- .\" * MAIN CONTENT STARTS HERE * .\" ----------------------------------------------------------------- .SH "NAME" timesyncd.conf, timesyncd.conf.d \- Network Time Synchronization configuration files .SH "SYNOPSIS" .PP .RS 4 /etc/systemd/timesyncd\&.conf .RE .RS 4 /run/systemd/timesyncd\&.conf .RE .RS 4 /usr/local/lib/systemd/timesyncd\&.conf .RE .RS 4 /usr/lib/systemd/timesyncd\&.conf .RE .RS 4 /etc/systemd/timesyncd\&.conf\&.d/*\&.conf .RE .RS 4 /run/systemd/timesyncd\&.conf\&.d/*\&.conf .RE .RS 4 /usr/local/lib/systemd/timesyncd\&.conf\&.d/*\&.conf .RE .RS 4 /usr/lib/systemd/timesyncd\&.conf\&.d/*\&.conf .RE .SH "DESCRIPTION" .PP These configuration files control NTP network time synchronization\&. See \fBsystemd.syntax\fR(7) for a general description of the syntax\&. .SH "CONFIGURATION DIRECTORIES AND PRECEDENCE" .PP The default configuration is set during compilation, so configuration is only needed when it is necessary to deviate from those defaults\&. The main configuration file is loaded from one of the listed directories in order of priority, only the first file found is used: /etc/systemd/, /run/systemd/, /usr/local/lib/systemd/ \&\s-2\u[1]\d\s+2, /usr/lib/systemd/\&. The vendor version of the file contains commented out entries showing the defaults as a guide to the administrator\&. Local overrides can also be created by creating drop\-ins, as described below\&. The main configuration file can also be edited for this purpose (or a copy in /etc/ if it\*(Aqs shipped under /usr/), however using drop\-ins for local configuration is recommended over modifications to the main configuration file\&. .PP In addition to the main configuration file, drop\-in configuration snippets are read from /usr/lib/systemd/*\&.conf\&.d/, /usr/local/lib/systemd/*\&.conf\&.d/, and /etc/systemd/*\&.conf\&.d/\&. Those drop\-ins have higher precedence and override the main configuration file\&. Files in the *\&.conf\&.d/ configuration subdirectories are sorted by their filename in lexicographic order, regardless of in which of the subdirectories they reside\&. When multiple files specify the same option, for options which accept just a single value, the entry in the file sorted last takes precedence, and for options which accept a list of values, entries are collected as they occur in the sorted files\&. .PP When packages need to customize the configuration, they can install drop\-ins under /usr/\&. Files in /etc/ are reserved for the local administrator, who may use this logic to override the configuration files installed by vendor packages\&. Drop\-ins have to be used to override package drop\-ins, since the main configuration file has lower precedence\&. It is recommended to prefix all filenames in those subdirectories with a two\-digit number and a dash, to simplify the ordering\&. This also defines a concept of drop\-in priorities to allow OS vendors to ship drop\-ins within a specific range lower than the range used by users\&. This should lower the risk of package drop\-ins overriding accidentally drop\-ins defined by users\&. It is recommended to use the range 10\-40 for drop\-ins in /usr/ and the range 60\-90 for drop\-ins in /etc/ and /run/, to make sure that local and transient drop\-ins take priority over drop\-ins shipped by the OS vendor\&. .PP To disable a configuration file supplied by the vendor, the recommended way is to place a symlink to /dev/null in the configuration directory in /etc/, with the same filename as the vendor configuration file\&. .SH "OPTIONS" .PP The following settings are configured in the [Time] section: .PP \fINTP=\fR .RS 4 A space\-separated list of NTP server host names or IP addresses\&. During runtime this list is combined with any per\-interface NTP servers acquired from \fBsystemd-networkd.service\fR(8)\&. \fBsystemd\-timesyncd\fR will contact all configured system or per\-interface servers in turn, until one responds\&. When the empty string is assigned, the list of NTP servers is reset, and all prior assignments will have no effect\&. This setting defaults to an empty list\&. .sp Added in version 216\&. .RE .PP \fIFallbackNTP=\fR .RS 4 A space\-separated list of NTP server host names or IP addresses to be used as the fallback NTP servers\&. Any per\-interface NTP servers obtained from \fBsystemd-networkd.service\fR(8) take precedence over this setting, as do any servers set via \fINTP=\fR above\&. This setting is hence only relevant if no other NTP server information is known\&. When the empty string is assigned, the list of NTP servers is reset, and all prior assignments will have no effect\&. If this option is not given, a compiled\-in list of NTP servers is used\&. .sp Added in version 216\&. .RE .PP \fIRootDistanceMaxSec=\fR .RS 4 Maximum acceptable root distance, i\&.e\&. the maximum estimated time required for a packet to travel to the server we are connected to from the server with the reference clock\&. If the current server does not satisfy this limit, \fBsystemd\-timesyncd\fR will switch to a different server\&. .sp Takes a time span value\&. The default unit is seconds, but other units may be specified, see \fBsystemd.time\fR(5)\&. Defaults to 5 seconds\&. .sp Added in version 236\&. .RE .PP \fIPollIntervalMinSec=\fR, \fIPollIntervalMaxSec=\fR .RS 4 The minimum and maximum poll intervals for NTP messages\&. Polling starts at the minimum poll interval, and is adjusted within the specified limits in response to received packets\&. .sp Each setting takes a time span value\&. The default unit is seconds, but other units may be specified, see \fBsystemd.time\fR(5)\&. \fIPollIntervalMinSec=\fR defaults to 32 seconds and must not be smaller than 16\ \&seconds\&. \fIPollIntervalMaxSec=\fR defaults to 34\ \&min\ \&8\ \&s (2048\ \&seconds) and must be larger than \fIPollIntervalMinSec=\fR\&. .sp Added in version 236\&. .RE .PP \fIConnectionRetrySec=\fR .RS 4 Specifies the minimum delay before subsequent attempts to contact a new NTP server are made\&. .sp Takes a time span value\&. The default unit is seconds, but other units may be specified, see \fBsystemd.time\fR(5)\&. Defaults to 30 seconds and must not be smaller than 1 second\&. .sp Added in version 248\&. .RE .PP \fISaveIntervalSec=\fR .RS 4 The interval at which the current time is periodically saved to disk, in the absence of any recent synchronisation from an NTP server\&. This is especially useful for offline systems with no local RTC, as it will guarantee that the system clock remains roughly monotonic across reboots\&. .sp Takes a time interval value\&. The default unit is seconds, but other units may be specified, see \fBsystemd.time\fR(5)\&. Defaults to 60 seconds\&. .sp Added in version 250\&. .RE .SH "SEE ALSO" .PP \fBsystemd\fR(1), \fBsystemd-timesyncd.service\fR(8), \fBsystemd-networkd.service\fR(8) .SH "NOTES" .IP " 1." 4 ๐Ÿ’ฃ๐Ÿ’ฅ๐Ÿงจ๐Ÿ’ฅ๐Ÿ’ฅ๐Ÿ’ฃ Please note that those configuration files must be available at all times. If /usr/local/ is a separate partition, it may not be available during early boot, and must not be used for configuration.